Gas filled discharge tube



Aug. 30, 1932. G. L. HERTZ GAS FILLED DISCHARGE TUBE Filed Dec. 15. 1926 Patented Aug. 30, 1932 UNITED STATES PATENT. OFFICE GUSTAV L'UDWEG HERTZ, 6F HALLE-ON-THE-SAALE, GERMTANY, ASSEGNOB TO N. V. PHILIPS GLOEILAMPENFABRIEKEN, OF EINDHOVEN, NETHERLANDS, A LIMITED LIABILITY COMPANY OF THE NETHERLANDS GAS FILLED DISCHARGE TUBE Application filed December 13, 19.26, Serial No. 154,550, and in the Netherlands December 16, 1925.

The invention relates to gas filled discharge devices and more particularly to devices comprising a solid incandesible electrode and a cold electrode.

The invention has for its object to provide a gas filled discharge tube which is adapted to rectify alternating currents and may be operated at very high voltages.

If an alternating current is supplied to a gas filled discharge device provided with a cold electrode and a solid incandescible electrode, comprising an electron emitting material, the current will pass during the half cycle in which the cold electrode is positively charged owing to the fact that electrons 5 unidirectional, though the voltage applied to the electrodes is alternating. The discharge tube then acts as a rectifier.

By increasing the voltage a certain value may be attained where ignition also occurs during the half cycle in which the in-candescible electrode is positively charged. Operated at such a voltage the tube practically no longor serves as a rectifier.

Applicant has found that this critical value of the operating voltage, above which a breakdown ensues in the direction from the solid incandescible electrode to the cold electrodes is materially increased if the cold electrode, which is intended to act as an anode, is screened by a conductive body. The distance between the body and the screened electrode must preferably be in agreement with, or if possible, smaller than the distance through which the first dark space extends during discharge.

In a construction of the discharge tube according to the invention an incandescible cathode for example an oxide cathode, may be used as the active cathode. The anode may be cylindrical and bear by its outer surface on the wall of the tube, the inner surface being screened by a cylinder which is axially arranged within the anode cylinder at a small intermediate space. a determined potential to the covering body but in some cases this may be advantageous.

The anode may be made of good heat conducting material, for example copper. The cathode is preferably arranged on one of the two sides of the coaxial cylinders approximately on their axes.

co ensure that the point of ignition to be attained in the. direction from the screened electrode to the incandescible cathode, shall be as high as possible, the first mentioned electrode is in the said construction provided with a very slanting edge on that side adjacent to the other electrode.

In order to provide for an equal distance at any point between the anode and the screening element glass spacing sticks are provided having a diameter equal to the desired space between the two cylinders.

The invention may be more clearly understood by reference to the accompanying drawing in which one embodiment is illustrated. In the drawing:

Fig. 1 shows in elevation an incandescent cathode discharge tube according to the invention.

Fig. 2 is a section taken on the line 11-11 Fig. 1.

Fig. 3 is a vertical partial section of the screened electrode by a plane passing through the axis of this electrode.

Referring to Fig. 1 numeral 1 designates a gas filled discharge tube, 3 is a cylindrical conductive body, by which the cylindrical anode 2 is screened; 4c is an incandescent cathode, 5 and 6 are leading-in wires to the oathode and 7 is one of the glass spacing sticks separating the two cylinders.

What I claim is 1. A gas filled electron discharge rectifier, comprising a solid incandescible cathode, an anode and an imperforate conductive body, said body screening the anode for the purpose of preventing a discharge in the wrong direction.

2. A gas filled electron discharge rectifier,

It is not essential to give comprising a solid incandesoible cathode, an

anode and an imperforate conductive body at a distance from the anode substantially that of the distance through which the first dark space extends during discharge for the purpose of preventing a discharge in the wrong direction.

3. A gas filled electron discharge rectifier comprising the combination of a solid incandescible cathode, an annular shaped anode and a coaxial cylindrically shaped conductive body within said anode and spaced therefrom an insulating d stance, screening the anode for preventing the discharge in the wrong direction.

4. A gas filled electron discharge rectifier comprising the combination of a solid incandescible cathode, an annular shaped anode having a sharp slanting edge at the end toa ward thecathode, and a coaxial cylindrically V shaped conductive body within said anode and spaced therefrom an insulating distance, screening the anode for preventing the discharge in'the wrong direction.

In testimony whereof I afiix my signature at the city of Leipzig, this 23d day of N ovember, 1926.

- GUSTAV LUDWIG HERTZ. 

